1. Field of the Invention
The present invention relates to a portable setting tool for fastening elements and including a housing, a guide tube for guiding the fastening elements, connectable with the housing and having a side cut-out through which the fastening elements are fed into the guide tube, and a feeler extendable into the guide tube at a location opposite the cut-out of the guide tube and displaceable in a direction away from the guide tube.
2. Description of the Prior Art
A setting tool of a type described above is disclosed in a German Publication DE-19950 349A1. The setting tool includes a guide tube for guiding the fastening elements and having a side cut-out through which the fastening elements are fed into the guide tube, and a feeler engaging into the guide tube at a location opposite the cut-out of the guide tube and displaceable in a direction away from the guide tube.
For ejecting a fastening element from the guide tube, a piston rod of a piston in driven into the guide tube, impacting the fastening element. A piston plate, which is connected with the piston rod, adjoins a combustion chamber. The piston drive energy is generated by ignition of a suitable combustible gas mixture, e.g., air/fuel gas mixture.
For safety reason, in setting tools described above, often, a press-on sleeve which is slidably supported on the guide tube, is used. The press-on sleeve insures that a setting process, i.e., driving of a fastening element in an object only then becomes possible when the setting tool is pressed against the object. When the setting tool is pressed against the object, the press-on sleeve is displaced against a biasing force rearwardly with respect to the guide tube. During its displacement, the press-on sleeve alternatively cooperates with mechanical locking means and/or mechanical or electrical switches which only then allow actuation of a trigger and/or release of the drive energy when the press-on sleeve was depressed by a predetermined minimum amount.
Setting tools of this type are often equipped with magazines and have additional locking functions associated with determination whether a magazine has been secured to the setting tool, whether the number of fastening elements in the magazine is sufficient, and whether the fastening elements are properly position in the magazine or the guide tube. Only when a positive determination has been made, the setting process can be initiated.
Preferably, the fastening elements are arranged in a strip or a band and in this condition are placed in the magazine. The displacement within the magazine is effected by a biasing force so that a next fastening element can be advanced in the guide tube and be driven into an object.
If the setting tool is equipped with a feeler of the type described above, the pressure of a fastening element in the guide tube is determined based on a projecting depth of the feeler into the guide tube. The feeler also permits to determine whether the fastening element occupies a correct position in the guide tube. When there is no fastening element in the guide tube or the fastening element has not been advanced sufficiently far into the guide tube, the feeler can project into the guide tube so far that effecting a setting process or initiation of the ignition, associated with the setting process is not possible. The operation of the setting tool is blocked until a fastening element is properly positioned in the guide tube, which corresponds to a minimal penetration depth of the feeler.
Further, during setting of fastening elements, from time to time, either a fastening element or the fastening element-carrying strip breaks and becomes jammed in front or behind the feeler. Then, a regular operation of the setting tool is not possible.
Accordingly, an object of the invention is to so improve a setting tool of the type described above that clearing of the guide tube from pieces of a broken fastening element or strip can be easily effected without a danger of damaging the feeler.
This and other objects of the present invention, which will become apparent hereinafter are achieved by providing a setting tool with a feeler that has at its end extendable into the guide tube, an adjusting rim forming, with a longitudinal axis of the guide tube, an acute angle opening in a direction toward a mouth opening of the guide tube.
In case when a broken piece of a fastening element or of a fastening element holder becomes jammed in the guide tube in the region of the feeler, the broken piece can be easily removed by inserting a clearing tool in the guide tube from the guide tube mouth opening. The broken piece or the clearing tool, by engaging the adjusting rim, easily displaces the feeler radially outwardly, so that the broken piece is easily pushed out of the guide tube. The easy radial displacement of the feeler eliminates any danger of the feeler being damage. This significantly increase the service life of a guide tube unit that includes the feeler.
According to a further development of the present invention, there is provided, at the end of the feeler extendable into the guide tube, another adjusting rim that forms with the longitudinal axis of the guide tube an acute angle opening in a direction opposite the mouth opening of the guide tube. The other adjusting rim insures an easy removal of jammed piece from the setting tool side of the guide tube. This is because the feeler will also be displaced radially outwardly with the broken piece or the clearing tool, without being damaged. A clearing tool can be formed as a clearing rod insertable into the guide tube.
As it follow from the foregoing description, the broken pieces, which are located immediately in front and/or behind the feeler are easily removed, without damaging the feeler. As even in this case, it is insured that the feeler is easily displaced radially outwardly by the broken pieces, without being damaged, due to the adjusting rims. Advantageously, clearing of the guide tube is effected after the guide tube has be lifted off the setting tool.
When both adjusting rims of a feeler, which projects into the guide tube to a full extent, lie in the inner circumferential region of the guide tube, the rod-shaped clearing tool could have a maximal diameter only slightly smaller than the inner diameter of the guide tube. In this case, it is always insured that the clearing tool is advanced against the slope of the first or second adjusting rim for displacing the feeler radially outwardly, without damaging the feeler.
Generally, the feeler is displaced linearly into and out of the guide tube. However, the feeler can also be pivotally arranged so that it would pivot into or out of the guide tube.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to is construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments, when read with reference to the accompanying drawings.